1. Field of the Invention
The invention relates to an air regulator for compressors, especially screw compressors, which have an oil separator apparatus with a pre-separator, and a regulator housing with a spring-loaded valve element which can be actuated by means of a piston arrangement.
2. Description of Related Art
It is generally known that regulators can either be designed such that they are open in the base state or are closed in the base state. Regulators which are closed in the base state are used especially in screw compressors in order to avoid high-inertia starting, mainly when cold. Generally, the starting of such a screw compressor is at first also enabled using the regulator which is closed in the base state. Such a regulator which is closed in the base state has a strong pretensioning spring which keeps the regulator in its closed position during starting or relief. As a result of the high spring forces in this regulator, unfavorable behavior results with respect to the control quality and control rate.